Solar activity increased to moderate levels. Region 338 (N18W05) produced an M2/1n flare at 21/1307Z. Considerable radio emissions were associated with this flare, including a Type II (1200 km/s) and Type IV sweep, and a 300 sfu tenflare. A partial halo CME was also noted from LASCO imagery. This beta-gamma region is in a slow growth phase with a moderate increase in the number of sunspots visible over the past 24 hours. Region 337 (S13E43) is the largest and most complex region on the visible disk, and now contains a weak delta configuration in the 350 millionths of white light areal coverage. Only minor C-class flares have been observed so far from this region. Minor C-class activity was also observed in Region 339 (N16W58). New Regions 340 (S04E55), and 341 (S10E74), were numbered today.

Solar activity is expected to be low to moderate. An isolated M-class flare is possible from Regions 337 or 338.

The geomagnetic field was at predominantly unsettled to active levels with isolated high latitude minor storm periods. A high speed solar wind stream, with winds ranging from 520 - 600 km/s, continues to buffet the geomagnetic field. The greater than 2 MeV electrons at geosynchronous orbit reached high levels.

The geomagnetic field is expected to be at unsettled to active levels through day one. Minor storm periods are possible on days two and three with the anticipated arrival of the CME from today's M2 flare.

  Спостережуваний       21 Apr 126
  Прогнозований   22 Apr-24 Apr  135/140/145
  Середнє значення за останні 90 днів        21 Apr 126

  Спостережуваний Afr/Ap 20 Apr  012/016
  За оцінками     Afr/Ap 21 Apr  015/020
  Прогнозований    Afr/Ap 22 Apr-24 Apr  012/015-020/030-020/030